| Correct nutrition in Parkinson’s disease |
|
The importance of one’s diet, intended not as a dietary regimen based on sacrifice or deprivation, but as nutritional habits designed to preserve health satisfactorily, is well known. In the presence of chronic disease a dietary regimen is essential for well-being. The objective of these pages is to help patients with Parkinson' s disease and their families understand how and to what extent correct nutrition potentiates the efficacy of pharmacological therapy and improves general conditions. Indeed clinical trials have demonstrated scientifically and patients have experienced personally that a low-protein lunch improves the efficacy of levodopa-based pharmacological therapy and that a balanced dietary regimen reduces the risk of metabolic diseases (high cholesterol, diabetes, gout), of cardiovascular disorders and of disorders affecting the skeleton and the joints. A special diet for patients with Parkinson’s disease The requirement for a special dietary regimen for patients suffering from Parkinson’s disease on treatment with levodopa results from the awareness that meals can interfere with the efficacy of pharmacological therapy. Levodopa is a neutral amino acid that has to be actively transported (i.e. requires transportation that consumes energy) to be absorbed i.e. to move from the intestine to the bloodstream and ultimately to the brain. Therefore, it is easy to understand that anything that slows down absorption from the intestine may reduce the quantity of drug that is available for transportation to the brain. This, in turn, reduces the effects of pharmacological therapy. Pharmacokinetics of levodopa Levodopa is not absorbed in the stomach, which serves only as a passage to the small intestine, where the drug is absorbed. However, the length of time levodopa remains in the stomach is important, because the drug is degraded by gastric enzymes. Consequently, the longer it stays in the stomach, the more it is degraded and loses its efficacy. There are several dietary factors that influence the rate of gastric emptying. Fats require the most time for digestion, followed by proteins and carbohydrates. Also fibers slow gastric emptying down. Excessive gastric acidity and some drugs, such as anticholinergics, have the same effect. Studies in patients with excessive gastric acidity have shown that antacids improve levodopa absorption by reducing gastric acidity. Acid agents in patients with slowed gastric emptying promote absorption of the drug in the same way. Consequently, neither a lack or an excess of acid in the stomach facilitates optimal absorption of the drug. Furthermore, also constipation may reduce the absorption of the drug. Studies have compared the absorption of levodopa after a single administration on an empty stomach as compared to the quantity absorbed during a meal. The comparison clearly showed that intake of the drug during a meal significantly delays its efficacy. Levodopa is absorbed into the bloodstream after it has passed through the stomach and has reached the small intestine. Levodopa is a neutral amino acid that requires active transport to be absorbed. This applies not only to the passage from the gut to the bloodstream, but also the passage through the blood-brain barrier. Indeed, different transport systems for the various types of basic, acid, neutral and aromatic amino acids exist. These transport systems are active i.e. they consume energy and are specific for particular amino acid classes. Consequently, all aromatic amino acids originating from ingested proteins with a meal use the same transportation system as levodopa and compete with it. These amino acids are: Isoleucine, leucine, valine, phenylalanine, tryptophan and tyrosine. Meals rich in protein, especially in these amino acids, may therefore interfere with the pharmacological activity of levodopa, making carriers essential for transport. A group of patients received infusions of levodopa so that steady state levels of the drug were achieved and, consequently, constant passage into the brain. In this way a more stable motor response was achieved with considerable reduction in fluctuations. Subsequently a solution containing one of the above listed amino acids was administered to the patients. It competed with levodopa for its specific transport system. Notwithstanding the continuation of levodopa infusion, patients became blocked or experienced severe impairment of motor function. This clearly shows that these amino acids compete with levodopa and may prevent it from reaching cerebral cells. A protein-rich meal has the same effect. All this shows that a low-protein diet may improve the efficacy of levodopa. Advice on how to take levodopa correctly Levodopa (Madopar and Sinemet) should be taken from 15 to 30 minutes before a meal so that it is absorbed properly. However, there are conditions in which it is better to not follow this rule, in order to reduce some bothersome side effects due to its intake in the fasting state: 1) should levodopa cause nausea it is advisable to take it with a small low-protein snack or, if necessary, during a meal; should this be insufficient, you can take domperidone (Peridon or Motilium), a medicine that acts peripherally increasing gastrointestinal motility and thereby controlling nausea and promoting the absorption of levodopa 2) when disturbing dyskinesias occur as soon as levodopa is taken Levodopa can be taken with a meal to control this phenomenon; in this way peak blood levels are reduced (should the dyskinesias be due to high peak blood levels) In some cases simple dietary advice does not suffice. In these cases one has to resort to a diet tailored to one's individual needs, including calculations of quantities in grams, which takes individual dietary habits and tastes into account, but at the same time controls daily protein intake. When even this does not suffice, one can resort to “special” foods. Low protein food products are on the market, which can simplify food preparation. These products enable the patient to maintain his dietary habits. Indeed, a broad range of foods are available that improve the efficacy of pharmacological therapy thanks to their low content in vegetable proteins. Figure SnackBreakfast Example of daily administrations of levodopa not to be taken with meals Overweightedness in PD patientsNowadays it is well known that obesity is a serious disorder that has a major impact on health in our country. Recent data show that the incidence of this disorder is rapidly increasing also in Italy: According to the last ISTAT estimates, today there are more than 4 million people in Italy who are obese – an increase by 25% over the incidence in 1994. One adult out of three is overweight (33.4%), 9.1% are obese, 53.8% have a normal weight and the remaining 3.6% are underweight. The data do not leave nutrition experts and researchers indifferent. For this reason we have assessed the nutritional status of PD patients. There are various factors that interfere with normal nutritional status in PD. In the literature there are many papers that indicate that the main nutritional issue in PD is underweight. Malnutrition is defined as a BMI below 18.5, BMI being the Body Mass Index, which is calculated dividing one’s weight in kg by the square of one’s height expressed in metres. In both sexes normal BMI is comprised within the interval between 18.5 and 24.9. A diagnosis of overweight is made when the BMI is between 25 and 29.9 and a diagnosis of obesity when BMI is over 30. Maintenance of adequate body weight is important for the survival of the individual and of the species. There has to be a balance between energy consumption and ingested calories for body weight to remain stable in the long term, not only in terms of energy, but also in terms of quality, so that the mixture of oxidized substrates corresponds quantitatively and qualitatively to the substrates ingested. Thus, it is evident that an imbalance between the introduction and consumption of energy leads to changes in fat content. Difficulties in swallowing and chewing, low socio-economic status, depression and, above all, severe dyskinesias are the main reason for weight loss, but there is also the opposite problem, malnutrition in excess that leads to overweightedness and obesity. The analysis of the anthropometric data of 364 PD patients with a mean age of 66 ± 9 years, 180 females and 184 males, disclosed that 62% of patients who attend our unit are overweight (BMI > 25) and that 26% of these are obese (BMI > 30). The analysis of the ISTAT 1999/2000 data related to subjects of the same age revealed that the rate of overweightedness is similar in the two populations, but that the rate of obesity is 50% higher in PD patients than in the reference Italian population and that only 3% of patients were underweight (BMI < 18,5). There is a correlation between years of disease and weight loss: during the first 10 years overweightedness is the main nutritional problem. Underweight patients who need a high-calory diet have a history on average of 14 years of disease as compared to a mean duration of disease of 10 years in the patients who need low-calory diets. There do not appear to be differences in BMI between the two sexes, between smokers and non smokers, between patients on treatment with levodopa and those on treatment only with a dopamine agonist. The proportion of patients who exercise regularly is 50% higher amongst patients with a normal body weight than in those who are overweight. We surmise that the reduction in motor activity that characterizes this disease produces a positive energy imbalance that inevitably leads to an increase in body weight when dietary habits are not adjusted. It is essential for patients with a chronic neurodegenerative disease to have a normal weight for their height. Being underweight or overweight shortens the life expectancy of the patients and inevitably promotes the development of other metabolic disorders that may worsen the course of PD: Blood tests should be carried out routinely and a consultation with an expert in nutrition may improve the health of the patient and facilitate the symptomatic treatment of the neurological disease.
Calculate your BMI using the following formula BMI weight (Kg) Height x height (expressed in meters) Example A man who is one meter and seventy centimeters tall and who weighs 71 kilograms is to divide his body weight (i.e. 71) by the square of his height (1.7 x 1.7 = 2.89) The operation to be performed is therefore 71/2.89 = 24.6 Now compare the result obtained with the data in the table below Results Less than 18.5 underweight Between 18.5 and 24.9 Normal weight Between 25 and 29.9 Overweight More than 30 obese Now repeat the calculation with your own data If your weight is NOT NORMAL you should consult an expert in nutrition This reduces the risk of metabolic disorders and increases your life expectancy The balanced dietA balanced diet must be varied. The first, very important rule for correct nutrition is that food and recipes for the preparation of meals should vary. Only in this way can we meet the needs for all nutrients of our body. There is no food that is absolutely “bad” or “good”. For this reason one should always taste new food and change the way of cooking and preparing dishes. FigureDaily energy intake (expressed as calories) should be subdivided as follows: Breakfast 20%Lunch 35%Snack 10%Dinner 35% It is important to have regular mealsA balanced diet includes the three main meals: Breakfast, lunch and dinner. Breakfast is a very important meal for the correct distribution of calories during the day. Unfortunately it is often underestimated or is inappropriate. An Italian breakfast always includes protein in milk or milk-derivatives (yogurt) and complex carbohydrates in cereal, toast, bread, dry biscuits or special cereals for breakfast, such as muesli or cornflakes. You may add a small amount of simple sugars (sugar, honey, jam) to make the meal more appetizing. Also the food for breakfast should be varied; you should change the kind of bread, biscuits and cereal and alternate between milk and yogurt. Lunch and dinner are the two main meals. They may include two courses (full meal) or only one ( for instance, only a first course for lunch and only a second course with bread for dinner). In particular cases, e.g. during journeys, you can replace one meal with a sandwich. The first course (pasta or rice) may be prepared in broth or as a dry course. The best kind of sauces for flavoring are simple ones based on vegetables. It is better to use home-made vegetable or meat broth, preferably after having removed the fat, rather than using ready-made concentrated cubes or granules. Two courses may be replaced by a complete single course that includes both pasta or rice and meat, fish or leguminous vegetables in a single recipe. Examples of a single complete course are pasta with meat sauce, rice with peas, pasta and beans, rice with fish, as well as pizza. The second course may be eaten once or twice a day. Second courses consist of meat, fish, eggs, cheese and leguminous vegetables; it is very important to vary this course. Vegetables, either fresh or cooked, should be eaten both for lunch and dinner. You may add one or two snacks consisting in fresh fruit in the middle of the morning and of the afternoon. It is always better to eat the whole fruit instead of fruit juice. Fresh home-made orange or grapefruit juice is fine, but it should be drunk immediately after preparation, because vitamin C, which is contained in abundance in citrus fruit, degrades easily. Beverages You should drink at least 1.5 liters of water a day. This quantity should be increased if you perspire profusely and during the hot periods of the year. You may drink water with your meal or in-between meals. A good opportunity to learn to drink a lot is to drink a glass of water every time that you take your medication, besides what you drink during meals. Water does not contain calories and therefore does not make you gain weight, not even if it is fizzy. You should not drink too many drinks containing sugar, such as orange juice, coca cola and bottled cold tea, because their content in sugar is high. On the contrary, you may prepare tea with a few slices of lemon or camomile tea with a little sugar to be drunk hot in winter or cold in summer. Wine and alcoholic beveragesPD and the medicinal products used for its therapy do not absolutely contraindicate small quantities of alcohol. If you want to drink wine with your meal, you should prefer red wine and not exceed 1-2 glasses a day. However, people who do not habitually drink alcoholic beverages should not start to drink them. You should remove spirits from your diet or at least limit their quantity.Coffee and teaYou should not drink more than two cups of coffee a day. It is important to take the sugar you use to sweeten beverages into account and to reduce its quantity to a minimum.The composition of a balanced dietThe ideal composition of a balanced diet should be as follows: Most of its energy (55-58%) should come from carbohydrates (cereals and their derivatives, potatoes), 25-30% from fat and 12-15% from protein. |